
Phyllodesmium poindimiei.

Phyllodesmium poindimiei.

Clownfish
(Amphiprion nigripes)
in sea anemone (Heteractis magnifica).

Sea Bunny Nudibranch (source).
Argentinian Orca beaching itself to catch a seal pup (source).

The mantis shrimp “spearing” the
head of a fish. Mantis shrimp wait for fish to swim near their burrow
and then strike with their claws and drag them into their burrows. Their
strikes are so strong that they have been known to smash aquarium
glass.

Horseshoe crabs can lay between 60,000 to 120,000 eggs. These eggs are laid in the sand or mud in batches of a few thousand at a
time, and take 2 weeks to hatch. Many are eaten by seabirds while
incubating. (source)